Typically, in storage products of a redundant array of independent disks (RAID), Topology Service is defined and implemented to manage an RAID group (RG) object and a LUN object. The RG object can be used to implement an RAID algorithm and the LUN object can be used to export a region of the RG to an upper layer. Provision Drive (PVD) object can be used to abstract some common disk attributes from different disks provided by vendors mainly for the purpose of managing the disks. To manage configuration of RG/LUN/PVD, their configuration data and metadata need to be stored in the disks.
When a RAID system is booted, the RAID system will load the configuration data and the metadata from the disks and create the RG object, the LUN object and the PVD object in the memory. Thus, the data configuration is vital and redundancy is required for storing in the disks. In some storage products, the configuration data will be stored in three disks and protected with RAID 1 algorithm.
In a RAID storage system, the system topology and objects provide background data together. After the system topology is set up, there are system threads to monitor the system RAID groups, which can be called as a background service. The background service will manage and protect data on the disks automatically, such as driver swapping, data rebuilding on a new driver and data verification, etc.
However, at present, when reading system configuration data from a disk storing configuration data during the booting of a RAID system, the whole RAID system will be in an unavailable state, thus failing to meet performance requirements of a storage system.